SMI South Central (Smoke Management Instructions) South Central Smoke Management Instruction

Fri May 22 14:30:06 PDT 2009

SMOKE MANAGEMENT FORECAST AND INSTRUCTIONS
SALEM FORESTRY WEATHER CENTER
OREGON DEPARTMENT OF FORESTRY

ISSUED: Friday, May 22, 2009       2:40 PM      Jim Trost

1.  DISCUSSION AND FORECAST FOR SOUTH CENTRAL OREGON ZONES 624 AND 625

Weak ridge over the area.  A minor short-wave crosses to the north.  Still, when the influence of this trough combines with afternoon heating, there exists the slightest chance of afternoon thunderstorms.  In the lower levels, the air mass just stable enough that mixing will be slightly limited.  Overnight a strong surface based inversion brings the mixing height down to less than 500 feet.  Transport wind light in the morning, then increases from the northwest.  Biggest are nighttime smolder, poor dispersion except in the heat of the afternoon, and the upcoming Memorial Day weekend.  Recommend backing off from burning near SSRAs or recreation areas for the weekend.

    OUTLOOK (SUNDAY - TUESDAY):

Over the weekend, the air mass continues to gradually stabilize.  Heating will provide good mixing in the afternoons but overnight mixing becomes very poor and smoke will tend to settle into the Basin.  Light overnight surface winds don't help either.  Chances of thunderstorms decrease but still cannot be totally ruled out for Sunday afternoon.  As mentioned above, recommend holding off burning through the weekend due to both dispersion and the holiday.

2.  DISPERSION

SATURDAY
Mixing height 2300 - 3300 ft during the morning.  Afternoon mixing height rises to 4200 - 5000 ft then lowers to 1100 - 2100 ft in the evening.  Overnight the mixing height falls below 500 ft.

Transport wind NW to N at 4 - 8 mph during the morning, WNW to NW at 9 - 15 mph during the afternoon and NW to NNW at 15 - 25 mph in the evening.

Surface wind light and variable, controlled by local terrain, during the morning.  Surface wind WNW to NW at 8 - 12 mph in the afternoon and evening.

OUTLOOK:

SUNDAY
Mixing height below 1000 ft early, rising to 3800 - 4800 ft by late morning and through the afternoon.  Transport wind N to NE at 8 - 14 mph in the morning and NNW to N at 10 - 22 mph during the afternoon.  Surface wind light and variable, becoming WNW to NNW at 9 - 15 mph during the afternoon.

MONDAY
Mixing height below 1000 ft early, 3100 - 4100 ft by late morning, and 4300 - 5000 ft in the afternoon.  Transport wind N to NE at 5 - 9 mph during the morning and NW to N at 8 - 12 mph during the afternoon.  Surface wind N to NE at 4 - 8 mph during the morning, becoming WNW to NNW at 5 - 9 mph during the afternoon.

TUESDAY
Mixing height below 1000 ft early, 3000 - 4000 ft by late morning, and 3900 - 4900 ft in the afternoon.  Transport wind light and variable in the morning, becoming W to NW at 4 - 8 mph during the afternoon.  Surface wind light and variable, becoming WNW to NNW at 6 - 10 mph during the afternoon.

3.  BURNING INSTRUCTIONS FOR ZONES 624 AND 625 INCLUDING THE WALKER
    RANGE PORTION OF ZONE 624
This instruction is valid for burning conducted on Saturday, May 23, 2009.
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Avoid ignitions within 15 miles to the W through N of SSRAs.  For units that will smolder into the night, avoid burning within at least 30 miles to the W through NE in or near drainages leading to SSRAs.  Verify transport winds away from SSRAs if burning in any other direction.  Recommend against burning units that will smolder significantly overnight.

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4.  SPECIAL NOTE:

    The smoke management forecaster is available at (503)
    945-7401.  The smoke management forecaster is available
    to discuss specific burns.  The duty forecaster phone
    number is (503) 945-7401. Please call this number and
    not individual's numbers to discuss daily burning. Please
    avoid calling before 8 a.m. and between 2 to 3 p.m.

    This forecast is available on the Internet at:
      http://oregon.gov/ODF/FIRE/fire.shtml/#Smoke_Management

    Please ensure your units have been planned and accomplished by checking:
      http://oregon.gov/ODF/FIRE/SMP/dailysmoke.shtml

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